Uplink channel compensation for touchscreen devices

Abstract

An apparatus and method for compensating the effect of a contact by a hand or other body part of a user with a touch screen while holding an input device on the strength of a capacitively coupled uplink signal provided to the input device by a host device, by detecting and/or discriminating the body touch and modifying at least one uplink channel parameter.

The invention claimed is: 
     
       1. An apparatus comprising:
 a body touch detector for detecting a body touch by a body portion of a user on a touch screen during a concurrent touch by an input device; and 
 a modulator for changing a transmission parameter of an uplink channel from a touch screen driver of the touch screen to a receiver of the input device in response to the detected body touch, 
 wherein the modulator is configured to modify the uplink channel by temporarily increasing an amplification factor of the touch screen driver in response to the detected body touch or by signalling a body touch feedback signal, used for increasing a sensitivity of the receiver, to the input device in response to the detected body touch. 
 
     
     
       2. The apparatus of  claim 1 , wherein the apparatus comprises a wireless communication unit for signalling the body touch feedback signal to the input device. 
     
     
       3. A host device comprising an apparatus of  claim 1 , a touch screen and a touch screen driver. 
     
     
       4. A computer program embodied on a computer-readable storage device and comprising code configured to cause the apparatus of  claim 1  to perform a method comprising:
 detecting a body touch by a body portion of a user on a touch screen during a concurrent touch by an input device; 
 changing a transmission parameter of an uplink channel from a touch screen driver of the touch screen to a receiver of the input device in response to the detected body touch; and 
 performing the modification of the uplink channel by temporarily increasing an amplification factor of the touch screen driver in response to the detected body touch or by signalling a body touch feedback signal, used for increasing a sensitivity of the receiver, to the input device in response to the detected body touch. 
 
     
     
       5. The apparatus of  claim 1 , further comprising a sensitivity controller configured to control a sensitivity of the receiver in response to a receipt of the body touch feedback signal. 
     
     
       6. The apparatus of  claim 1 , further comprising a sensitivity controller configured to control a sensitivity of the receiver in response to a receipt of the body touch feedback signal, wherein the sensitivity controller is configured to increase the sensitivity of the receiver by initiating a gain control of an amplifier of the receiver. 
     
     
       7. The apparatus of  claim 1 , wherein the input device comprises a stylus or an eraser. 
     
     
       8. A host device comprising an apparatus of  claim 1 , a touch screen, a touch screen driver, and an input device. 
     
     
       9. An apparatus comprising:
 a communication unit for communicating with a host device of a touch screen; and 
 a sensitivity controller for controlling a sensitivity of a receiver for receiving an uplink signal from a touch screen driver of the touch screen, 
 wherein the communication unit is configured to receive a body touch feedback signal from the host device of the touch screen; and 
 wherein the sensitivity controller is configured to control the sensitivity of the receiver in response to a receipt of the body touch feedback signal. 
 
     
     
       10. The apparatus of  claim 9 , wherein the sensitivity controller is configured to increase the sensitivity of the receiver by initiating a gain control of an amplifier of the receiver. 
     
     
       11. An input device comprising an apparatus of  claim 9  and a receiver for receiving an uplink signal from a touch screen driver of a touch screen. 
     
     
       12. The input device of  claim 11 , wherein the input device comprises a stylus or an eraser. 
     
     
       13. A computer program embodied on a computer-readable storage device and comprising code configured to cause the apparatus of  claim 9  to perform a method comprising:
 receiving a body touch feedback signal from a host device of a touch screen; and 
 in response to receipt of the body touch feedback signal, controlling the sensitivity of a receiver that receives an uplink signal from a touch screen driver of the touch screen. 
 
     
     
       14. A host device comprising a touch screen, a touch screen driver, and an apparatus of  claim 9 . 
     
     
       15. A method comprising:
 detecting a body touch by a body portion of a user on a touch screen during a concurrent touch by an input device; 
 changing a transmission parameter of an uplink channel from a touch screen driver of the touch screen to a receiver of the input device in response to the detected body touch; and 
 modifying the uplink channel by temporarily increasing an amplification factor of the touch screen driver in response to the detected body touch or by signalling a body touch feedback signal, used for increasing a sensitivity of the receiver, to the input device in response to the detected body touch. 
 
     
     
       16. The method of  claim 15 , wherein signalling the body touch feedback signal comprises using a wireless communication unit to signal the body touch feedback signal to the input device. 
     
     
       17. The method of  claim 15 , further comprising controlling a sensitivity of the receiver in response to a receipt of the body touch feedback signal. 
     
     
       18. The method of  claim 15 , further comprising controlling a sensitivity of the receiver in response to a receipt of the body touch feedback signal, wherein controlling the sensitivity comprises increasing the sensitivity of the receiver by initiating a gain control of an amplifier of the receiver. 
     
     
       19. A computer program embodied on a computer-readable storage device and comprising code configured to cause a processor to perform the method of  claim 15 . 
     
     
       20. The method of  claim 15 , wherein the input device comprises a stylus or an eraser.